AGE AT ONSET, SEX, AND FAMILIAL PSYCHIATRIC MORBIDITY IN SCHIZOPHRENIA - CAMBERWELL COLLABORATIVE PSYCHOSIS STUDY

Background. Although a genetic component in schizophrenia is well esta blished, it is likely that the contribution of genetic factors is not constant for all cases. Several recent studies have found that the rel atives of female or early onset schizophrenic patients have an increas ed risk of schizophrenia, compared to relatives of male or late onset cases. These hypotheses are tested in the current study. Method. A fam ily study design was employed; the probands were 195 patients with fun ctional psychosis admitted to three south London hospitals, diagnosed using Research Diagnostic Criteria (RDC), and assessed using the Prese nt State Examination (PSE). Information on their relatives was obtaine d by personal interview of the mother of the proband, and from medical records. Psychiatric diagnoses were made using Family History- Resear ch Diagnostic Criteria (FH-RDC), blind to proband information. Results . There was a tendency for homotypia in the form of psychosis within f amilies. The lifetime risk of schizophrenia in the first degree relati ves of schizophrenic probands, and the risk of bipolar disorder in the first degree relatives of bipolar probands, were 5-10 times higher th an reported population risks. Relatives of female and early onset (<22 years) schizophrenic probands had higher risk of schizophrenia than r elatives of male and late onset schizophrenic probands. However, this effect was compensated in part by an excess of non-schizophrenic psych oses in the relatives of male probands. Conclusions. These results sug gest a high familial, possibly genetic, loading in female and early on set schizophrenia, but do not resolve the question of heterogeneity wi thin schizophrenia.